Body Weight Support System Research Articles

Design and Evaluation of an Integrated Active and Passive Body Weight Support System for Variable Gravity and Inertia Compensation

Design and Evaluation of an Integrated Active and Passive Body Weight Support System for Variable Gravity and Inertia Compensation

Design and Validation of an Ambulatory User Support Gait Rehabilitation Robot: NIMBLE

Relearning to walk requires progressive training in real scenarios—overground—along with assistance in basic tasks, such as balancing. In addition, user ability must be maximized through compliant robotic assistance as needed. Despite decades of research, gait rehabilitation robotic devices yield controversial results. This article presents the conceptual design of a novel walking assistance and rehabilitation robot, the NIMBLE robot, aimed at providing ambulatory, bodyweight-supported gait training, assisting the user’s center of mass trajectory to aid weight transfer and dynamic balance during walking. NIMBLE consists of a robotic mobile frame, a partial bodyweight support (PBWS) system, an ambulatory lower-limb exoskeleton (Exo-H3) and a cable-driven pelvis-assisting robot. Designed as a modular structure, it differentiates hierarchical communication levels through a Robot Operating System (ROS) 2 network. We present the mechatronic design and experimental results assessing the impact of the mechatronic coupling between the robotic modules on the walking kinematics and the frame movement control performance. The robotic frame hardly affects the walking kinematics up to 2 degrees in both the sagittal and frontal planes, making it feasible for lateral balance and weight translation training. Moreover, it successfully tracks and follows user trajectories. The NIMBLE robotic frame assessment shows promising results for ambulatory gait rehabilitation.

A New Variable-Stiffness Body Weight Support System Driven by Two Active Closed-Loop Controlled Drives

A New Variable-Stiffness Body Weight Support System Driven by Two Active Closed-Loop Controlled Drives

Development of a Body Weight Support System Employing Model-Based System Engineering Methodology

Partial body weight support systems have proven to be a vital tool in performing physical therapy for patients with lower limb disabilities to improve gait. Developing this type of equipment requires rigorous design process that obtains a robust system, allowing physiotherapy exercises to be performed safely and efficiently. With this in mind, a “Model-Based Systems Engineering” design process using SysML improves communication between different areas, thereby increasing the synergy of interdisciplinary workgroups and positively impacting the development process of cyber-physical systems. The proposed development process presents a work sequence that defines a clear path in the design process, allowing traceability in the development phase. This also ensures the observability of elements related to a part that has suffered a failure. This methodology reduces the integration complexity between subsystems that compose the partial body weight support system because is possible to have a hierarchical and functional system vision at each design stage. The standard allowed requirements to be established graphically, making it possible to observe their system dependencies and who satisfied them. Consequently, the Partial Weight Support System was implemented through with a clear design route obtained by the MBSE methodology.

Harnessing Mobility: A Medically Complex Child's Home Program Utilizing an In-Home Body Weight Support System.

To describe a home program for a child with medical complexity using an over-ground body weight support (BWS) system. Children with medical complexity often use home programs due to challenges with regular therapy attendance. In this case, effective home program components including child centered design, family leadership, and best practice principles were prioritized around the PUMA (portable mobility aid for children). This BWS system was to be used for 1 hour per day to support mobility and active play. The CMC and family demonstrated high adherence, using over-ground BWS 87% of the 135 days it was accessible with an average daily usage of 59 min spread across 1-3 bouts per day. The average daily fun index during usage was 7/10. This home program demonstrated over-ground BWS technology as a feasible, fun platform for functional mobility and socialization in a child with significant medical and physical limitations.

Self-paced heart rate control during treadmill exercise for persons with gait impairment: a case study

Introduction:A self-paced (SP) heart rate (HR) control system proposed in a previous study was found to be feasible for healthy participants. The aims of this work were to investigate whether the SP HR control system is feasible to achieve accurate HR control in a participant with gait impairments, and to assess its interaction with an existing motor-driven body weight support (BWS) system.Methods:One participant with cerebral palsy was recruited in this case study. Three preliminary tests were completed to determine the appropriate mean value and amplitude of the target heart rate curve, and to identify a customised heart rate response model. Two series of formal self-paced heart rate control tests were then conducted to investigate the influence of different heart rate compensators and the presence of the BWS system.Results:The customised heart rate controller achieved improved accuracy in heart rate control and reduced oscillation in the treadmill target speed: the root-mean-square heart rate tracking error (RMSE) was 2.38 beats per minute (bpm) vs. 3.91 bpm (customised controller vs. nominal controller), and the average power of changes in the treadmill target speed was 0.4 × 10−4 m2/s2 vs. 8.4 × 10−4 m2/s2. The BWS system resulted in improved HR tracking accuracy: RMSE on heart rate tracking was 3.02 bpm vs. 3.50 bpm (with BWS vs. without BWS). The BWS system had no influence on the automatic position control accuracy: RMSE on distance tracking was 0.0159 m vs. 0.0164 m.Conclusion:After customising the heart rate compensator, the self-paced heart rate control system is feasible to achieve accurate heart rate control in an individual with gait impairments, and it can correctly interact with the BWS system.

The effectiveness of bodyweight-supported treadmill training in stroke patients: randomized controlled trial.

This study aimed to assess the impact of conventional rehabilitation (CR) and the combination of bodyweight-supported treadmill training (BWSTT) with CR on walking speed, endurance, balance, mobility, and the quality of life in stroke survivors. In this prospective, randomized, controlled, and single-blind study, 30 stroke patients were included (ClinicalTrials.gov registration number: NCT04597658 date: October 22, 2020). These patients were divided into two groups: (1) CR only (control group, n = 14) and (2) CR with BWSTT (experimental group, n = 16). Both groups received CR for 3 consecutive weeks, 5days a week, for 30min each day. The experimental group received an additional 30min of BWSTT per session. Patients were evaluated using the 10-m walk test (10MWT), the six-minute walk test (6MWT), the Tinetti Balance and Gait Assessment Score, the Timed Up and Go (TUG) test, the Rivermead Mobility Index (RMI), and the Stroke-Specific Quality of Life Scale (SS-QOL) before and after the intervention. Both groups showed significant improvements across all scales after the intervention. The BWSTT group exhibited particularly noteworthy enhancements in comfortable 10MWT and TUG scores (p = 0.043 and p = 0.025, respectively) compared to the CR group post-intervention. In conclusion, a holistic approach combining conventional physiotherapy with overground gait training can enhance various aspects of mobility. This approach offers a cost-effective and equipment-free alternative to BWSTT and necessitates specialized treadmill and bodyweight support systems, incurring higher costs. However, using BWSTT as a co-therapy therapy can be costly but provides additional benefits for enhancing functional mobility.

A novel computational framework for the estimation of internal musculoskeletal loading and muscle adaptation in hypogravity.

Introduction: Spaceflight is associated with substantial and variable musculoskeletal (MSK) adaptations. Characterisation of muscle and joint loading profiles can provide key information to better align exercise prescription to astronaut MSK adaptations upon return-to-Earth. A case-study is presented of single-leg hopping in hypogravity to demonstrate the additional benefit computational MSK modelling has when estimating lower-limb MSK loading. Methods: A single male participant performed single-leg vertical hopping whilst attached to a body weight support system to replicate five gravity conditions (0.17, 0.25, 0.37, 0.50, 1 g). Experimental joint kinematics, joint kinetics and ground reaction forces were tracked in a data-tracking direct collocation simulation framework. Ground reaction forces, sagittal plane hip, knee and ankle net joint moments, quadriceps muscle forces (Rectus Femoris and three Vasti muscles), and hip, knee and ankle joint reaction forces were extracted for analysis. Estimated quadriceps muscle forces were input into a muscle adaptation model to predict a meaningful increase in muscle cross-sectional area, defined in (DeFreitas et al., 2011). Results: Two distinct strategies were observed to cope with the increase in ground reaction forces as gravity increased. Hypogravity was associated with an ankle dominant strategy with increased range of motion and net plantarflexor moment that was not seen at the hip or knee, and the Rectus Femoris being the primary contributor to quadriceps muscle force. At 1 g, all three joints had increased range of motion and net extensor moments relative to 0.50 g, with the Vasti muscles becoming the main muscles contributing to quadriceps muscle force. Additionally, hip joint reaction force did not increase substantially as gravity increased, whereas the other two joints increased monotonically with gravity. The predicted volume of exercise needed to counteract muscle adaptations decreased substantially with gravity. Despite the ankle dominant strategy in hypogravity, the loading on the knee muscles and joint also increased, demonstrating this provided more information about MSK loading. Discussion: This approach, supplemented with muscle-adaptation models, can be used to compare MSK loading between exercises to enhance astronaut exercise prescription.

Effectiveness of Gait Training Using Dynamic Bodyweight Support System on Locomotor Abilities of Ambulatory Children With Different Neural Disorders

Background: In this study, we evaluated the efficacy of dynamic bodyweight-supported training on the gait quality of children with different neural disorders. Methods: Seventeen ambulatory children, aged 3 to 11 years, experiencing gait limitations, were selected to participate in the designed gait training program. Each child participated in 10 practice sessions held three days a week, with each training session using the dynamic body weight support system, comprising three stages, and lasting 20 minutes. Clinical assessments were conducted using four functional tests: "Five Time Sit to Stand Test (FSST)", "Modified Time Up and Go (MTUG)", "Time Up and Down Stairs (TUDS)", and "Pediatric Berg Balance Scale" (BBS). Results: Statistical tests demonstrated a significant increase in the post-values of the BBS after gait training. Notably, children with higher relative cognitive abilities showed more improvement. Additionally, there was a significant enhancement in the assigned score for the level of independence. As all participants had received conventional physical therapies for more than three years, reaching their maximum obtainable improvements with conventional training methods, the observed improvements could be attributed to the designed training protocol even without a control group. Conclusion: Designed gait training protocol using a dynamic weight support system proved effective in enhancing balance, improving gait quality, and increasing the level of independence during performing functional tests in ambulatory children suffering from different locomotor disabilities.

Design and optimization of a body weight support system for lower-limb rehabilitation robots considering vibration characteristics

Design and optimization of a body weight support system for lower-limb rehabilitation robots considering vibration characteristics

O13 Promoting an active lifestyle; use of an in-home body weight support system to increase exercise dosage for children with neuromuscular disease

O13 Promoting an active lifestyle; use of an in-home body weight support system to increase exercise dosage for children with neuromuscular disease

Harnessing the Power of Movement: A Body-Weight Support System & Assistive Robot Case Study.

Young children with motor disabilities face extra obstacles to engaging in movement and initiating social interaction. A body-weight support harness system (BWSS) allows a child to take steps, explore the environment, and interact with people and objects, but further research is needed to understand how this type of system can help children with motor disabilities. Assistive robots have the potential to keep a child engaged and motivated during physical therapy sessions with a BWSS. We conducted a case study over three and a half months to understand if the BWSS alone and if the BWSS with an assistive robot could promote child movement and engagement. Our results show that the child tended to increase their amount of movement over each session with the BWSS. The assistive robots used in this study also tended to keep the child engaged. The products of this work can benefit clinicians and researchers interested in early mobility intervention technologies, as well as roboticists working in the child mobility domain.

Do Patients with Parkinson's Disease Benefit from Dynamic Body Weight Support? A Pilot Study on the Emerging Role of Rysen.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor and non-motor alterations. Typical motor symptoms include resting tremors, bradykinesia (hypokinesia or akinesia), muscular stiffness, gait alterations, and postural instability. In this context, neurorehabilitation may have a pivotal role in slowing the progression of PD, using both conventional and innovative rehabilitation approaches. Thirty patients (15 males and 15 females) affected by PD were enrolled in our study. We randomly divided the patients into two groups, an experimental group (EG) and a control group (CG). In particular, the EG performed gait and balance training using the Rysen system, which is an innovative body weight support (BWS) system, whilst the CG received conventional physiotherapy. Both groups underwent 20 sessions, five times weekly, with each session lasting about 40 min. At the end of the training sessions (T1), we found that both groups (EG and CG) achieved clinical improvements, although the EG showed better scores for post-treatment regarding global motor functioning and postural stability compared to the CG. In conclusion, our results suggest that the Rysen system, which is an innovative BWS tool, could be considered a valid device for improving postural control and global motor functions, when compared to conventional gait training, in patients affected by PD.

High-strength and flexible mechanism for body weight support

Wearable body weight support systems can assist individuals with mobility impairments in performing daily living activities with greater ease and independence. However, existing systems have limitations in terms of balancing their strength, compact size, interaction with the ground, and driving. In this paper, we present the High-Strength and Flexible Mechanism (HSFM) designed for body weight support. The HSFM utilizes a coiling truss mechanism to perform flexible transformation between a straight and spiral shape. Its complex linkages create the mechanical constraints of the structure and enhance its stiffness. Additionally, the HSFM achieved a high extension rate, effective wire-driven mechanism, and smooth shift of the grounding point. We provide a detailed description of the HSFM, including the simplest 4-linkage mechanism, its mechanical constraints, and the wire-driven mechanism. Moreover, we conducted parametric analysis and geometric calculation on the link structure. The results justified the mechanical constraints of the HSFM and ensured the high extension rate. Further, its functionality for body weight support was evaluated with the hardware and showed sufficient results in terms of strength, smooth grounding, and wire-driven. This novel mechanism has the potential to develop a wearable body weight support robot enhancing daily living activities such as sit-to-stand transfer and walking.

A novel Dynamic Body Weight Support overground co-walker enabling variable unloading ratio and Motion Tracking.

Dynamic Body Weight Support (BWS) systems have gained attention in recent years for their potential in gait training. However, maintaining a natural gait and vertical unloading have been less explored. In our previous work, we developed a body Motion Tracking (MT) walker that can move with patients. In this study, we introduce a novel Motion Tracking Variable Body Weight Support (MTVBWS) system for overground walkers. This system utilizes Center of Mass (COM) tracking and gait phase detection to not only dynamically support the user's body weight in the vertical direction but also to facilitate movement in all directions. The system achieves this horizontal omnidirectional movement by employing active Mecanum wheels, guided by COM recognition. The validation experiments were implemented with the MT mode, passive mode, and BWS mode in "static," "fixed unloading ratio (FUR)," and "variable unloading ratio (VUR)" settings with unloading force of 20 and 30%. The result shows that, compared to other modes, the proposed system in the MTVBWS mode can reduce the dragging effect in the horizontal plane caused by the walker. Moreover, the unloading force can be adjusted automatically to minimize the fluctuations in the force experienced by each lower limb during the rehabilitation walking training process. In comparison to natural walk, this mode presents smaller force fluctuations for each lower limb.

A Performance Evaluation of Overground Gait Training With a Mobile Body Weight Support System Using Wearable Sensors

Overground gait training under body weight support (BWS) for patients who suffer from neurological injuries has been proven practical in recovering from walking ability. Conventionally, skilled therapists or additional robots are required to assist the patient’s body weight and pelvis movement, making the rehabilitation process physically and economically burdensome. We investigate if a BWS walker using only two actuators can support the user’s body weight and simultaneously protect/assist the transverse pelvis rotation, improving natural gait with minimal motion compensation. In this paper, a BWS strategy called transverse pelvis rotation support (TPRS) is proposed to enable the BWS system to generate cable tension in the forward direction, as a purpose to support transverse pelvis rotation in addition to our previously proposed static or variable BWS. Wearable sensory devices, including instrumented shoes and harness, were developed to provide real-time ground reaction force and pelvis rotation signals simultaneously. Ten non-disabled participants were unloaded with 0% ~ 15% BWS under four different controls. Vertical ground reaction force, transverse pelvis kinematics, and user experience were compared using proposed controls. One-Way repeated measures ANOVA analysis assessed if control strategies generally affect the performance. All proposed controls enable the walker to support part of the user’s body weight. SBWS-TPRS and VBWS-TPRS control enable users to achieve a significantly improved pelvic motion and prolonged single support phase than pure static BWS or variable BWS, although users perceive a higher workload under them. The proposed BWS controls show the potential to become a complementary method in gait rehabilitation.

Effect of bodyweight support and incline running on electromyographic activity of triceps surae

During rehabilitation, body weight support (BWS) system is often used. It can be useful for optimizing time to return to practice by unloading joints and muscles. The present study aimed to explore the effects of Body Weight Support (BWS) and Incline Running (IR) on electromyographic activity (EMG) of triceps surae. We hypothesized that running with a slope of 7% and 30% of BWS could result in EMG comparable to level running. Eighteen healthy individuals participated in four randomized experimental sessions of ten minutes run at 10 km/h: 1) level running and 0% of BWS (LR), 2) incline running at 7% and 0% of BWS, 3) incline running at 7% and 15% of BWS, 4) incline running at 7% and 30% of BWS. EMG activity of Vastus Lateralis (VL), Gastrocnemius Lateralis (GL), Gastrocnemius Medialis (GM), and Soleus (SOL) was recorded during each 10 minutes running conditions and before two times during 30 seconds level running to normalize EMG activity (baseline). In addition, gait spatiotemporal parameters were taken at 1’, 5’ and 9 minutes and Rating of Perceived Exertion RPE was asked at 5’, 7’, and 10 minutes. Tests were conducted before and two minutes after running conditions. They included Counter Movement Jump (CMJ), and quadriceps low-frequency fatigue test.The results of the present study revealed a significant decrease in electromyographic activity of SOL at IR at 30% of BWS condition compared to IR without BWS (P < 0.002). Moreover, a significant decrease in electromyographic activity was observed of VL at IR at 30% of BWS condition compared to level running and IR conditions without BWS (P < 0.002 and P < 0.001). No changes were found in jump test (P = 0.246) and gait spatiotemporal parameters (P > 0.05) except in flight time (decrease with IR, increase with BWS, P < 0.006). Rate of Perceived Exertion was decreased with 30% of BWS (P < 0.002) and was no different to level running (P = 0.079). 15% of BWS (vs. uphill without BWS) did not significantly decrease the difficulty perception (P = 0.570). Also, low-frequency fatigue of the quadriceps was induced without BWS (P = 0.011) but not with 15% and 30% BWS (P > 0.05)Our results show that EMG activity of the triceps surae can be similar between running on a flat surface and running on a slope and 30% BWS. Furthermore, muscle fatigue, perceived exertion rate and spatio-temporal running parameters were similar between running on a flat surface and 30% BWS at 7% IR. Therefore, it can be useful to optimize the return time to practice and it is recommending for monitoring loads in Achilles Tendon and triceps surae. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Simulation study on assist-as-needed control of a rehabilitation robotic walker.

Along with China entering an aging society, the percentage of people that over 60 will reach 34.9% in 2050, resulted in a significant increase in stroke patients. This paper proposes a rehabilitation robotic walker for walking assistance during the daily life, and a control method for the motor relearning during the gait training. The walker consists of an omni-directional mobile platform (OMP) which ensures the walker can move on the ground, a body weight support system (BWS) which is capable of providing the desired unloading force, and a pelvic assist mechanism (PAM) to provide the user with four degrees of freedom and avoid the rigid impact. The study goal is to gain a better understanding of the assist-as-needed control strategy during the gait training. For the man-machine interaction control, the assist-as-needed control strategy is adopted to guide the users' motions and improve the interaction experience. To build the force field in the three-dimensional space, the dynamics of the system is derived to increase the accuracy of force control. The simulation results show that the force field around the motion trajectory was generated in the three-dimensional space. In order to understand the force field, we designed the simulation on sagittal plane and the controller can generate the appropriate force field. The preliminary experiment results were consistent with the simulation results. Based on the mathematical simulation and the preliminary test, the results demonstrate that the proposed system can provide the guide force around the target trajectory, the accuracy of force control still remains to be improved.

Exploring the effects of body weight support systems on lower limb kinematics and muscle characteristics

Bipedal gait is one of the most important forms of human movement. However, every year many people lose their ability to walk due to disease. Weight support systems that reduce or even eliminate the effect of upper body mass loading on the lower limbs are among the most commonly used devices in gait rehabilitation. The designed weight support system provides body support while innovatively proposing a torso motion assist function. In this paper, walking experiments were performed on normal healthy subjects under five different weight-supported conditions, and motor and surface electromyography (sEMG) signals of the lower limb muscles were collected and analyzed. The results showed a slight decrease in joint motion of the lower extremities in the reference (free walking) and weight-supported-only assisted conditions, while there was no change in the joint angle curve waveform. In contrast, there was a significant change in the joint angle waveform between weight support plus trunk transfer and free walking. Different muscles differ in the significance of feature changes under different auxiliary conditions. By studying the changes in motor and muscle activation levels in the human lower extremity under the weight support system, it can be used as an indicator to assess specific gait indicators and muscle activity during the rehabilitation of the lower extremity in rehabilitated patients.

Lower Extremity Posture Assistive Wearable Devices: A Review

Many work-related tasks demand able-bodied employees to assume uncomfortable postures for long periods. This can lead to work-related musculoskeletal disorders. The situation demands the employees to be physically empowered while ensuring their agility and flexibility. In that context, wearable bodyweight support systems have come to the forefront as a futuristic solution to reduce the stress on the human body when assuming sitting and/or crouched postures. Recently, heightened attention on these posture assistive devices was evident with an increasing number of products, patents, and research articles. However, reviews of such wearable posture assistive devices for the lower limbs are lacking in the literature. Thus, this article specifically focuses on reviewing existing methods and technologies to assist workers in the industrial or service sectors to work in uncomfortable or crouched postures. Systematic reviews and meta-analyses extension for scoping reviews method was used to identify and analyze 43 unique designs from research and patent databases. The critical review of the technologies was performed after classifying these devices into commercial phase, lab/research phase, and conceptual design phase. This review has comprehensively covered the trends and patterns of the modern developments in posture assistance and includes future directions for the research community. Holistically, this article serves as a reference to set up a benchmarking system for wearable posture assistive devices.